@Test
public void test_empty() {
AVLTree<String, String> t = AVLTree.create();
assertThat(t).as("singleton").isSameAs(AVLTree.create());
assertThat(t.get("anything")).isNull();
assertThat(t.remove("anything")).isSameAs(t);
assertThat(t.toString()).isEqualTo("");
assertThat(t.hashCode()).isEqualTo(0);
}
@Test
public void buckets() {
Object k1 = new Key(42, "k1");
Object k2 = new Key(42, "k2");
Object k3 = new Key(42, "k3");
AVLTree<Object, Object> t = AVLTree.create().put(k1, "v1").put(k2, "v2");
assertThat(t.toString()).as("should create bucket").isEqualTo(" k2->v2 k1->v1");
AVLTree<Object, Object> t2 = AVLTree.create().put(k2, "v2").put(k1, "v1");
assertThat(t2.toString())
.as("toString depends on order of operations")
.isEqualTo(" k1->v1 k2->v2");
assertThat(t.equals(t2)).as("should compare buckets").isTrue();
assertThat(t2.equals(t)).as("should compare buckets").isTrue();
assertThat(t.hashCode())
.isEqualTo(
((31 * k1.hashCode()) ^ "v1".hashCode()) + ((31 * k2.hashCode()) ^ "v2".hashCode()));
assertThat(t2.hashCode())
.as("hashCode doesn't depend on order of operations")
.isEqualTo(t.hashCode());
assertThat(t.get(k1)).isEqualTo("v1");
assertThat(t.get(k2)).isEqualTo("v2");
assertThat(t.get(k3)).as("not such key").isNull();
assertThat(t.put(k2, "new v2").toString())
.as("should replace head of bucket")
.isEqualTo(" k2->new v2 k1->v1");
assertThat(t.put(k1, "new v1").toString())
.as("should replace element of bucket")
.isEqualTo(" k1->new v1 k2->v2");
assertThat(t.put(k1, "v1")).as("should not change").isSameAs(t);
assertThat(t.put(k2, "v2")).as("should not change").isSameAs(t);
assertThat(t.put(k3, "v3").toString())
.as("should add to bucket")
.isEqualTo(" k3->v3 k2->v2 k1->v1");
assertThat(t.remove(k2).toString()).as("should remove head of bucket").isEqualTo(" k1->v1");
assertThat(t.remove(k1).toString()).as("should remove element of bucket").isEqualTo(" k2->v2");
assertThat(t.remove(k1).remove(k2).toString()).as("should remove bucket").isEqualTo("");
assertThat(t.remove(k3)).as("should not change").isSameAs(t);
HashMap<Object, Object> biConsumer = new HashMap<>();
t.forEach((k, v) -> assertThat(biConsumer.put(k, v)).as("unique key-value").isNull());
assertThat(biConsumer).isEqualTo(ImmutableMap.of(k1, "v1", k2, "v2"));
HashSet<Object> consumer = new HashSet<>();
t.forEach(k -> assertThat(consumer.add(k)).as("unique key").isTrue());
assertThat(consumer).containsOnly(k1, k2);
}
@Test
public void test() {
List<Integer> keys = new ArrayList<>();
for (int i = 0; i < 100; i++) {
keys.add(i);
}
Collections.shuffle(keys);
AVLTree<Integer, Object> t = AVLTree.create();
for (Integer key : keys) {
t = t.add(key);
assertThat(t.add(key)).isSameAs(t);
}
assertThat(Counter.countSet(t)).isEqualTo(100);
assertThat(Counter.countMap(t)).isEqualTo(100);
assertThat(t.height()).isGreaterThanOrEqualTo(8).isLessThanOrEqualTo(10);
for (Integer key : keys) {
assertThat(t.contains(key)).isTrue();
t = t.remove(key);
assertThat(t.remove(key)).isSameAs(t);
}
assertThat(Counter.countSet(t)).isEqualTo(0);
assertThat(Counter.countMap(t)).isEqualTo(0);
}
@Test
public void hashCode_and_equals_should_not_depend_on_order_of_construction() {
Object o1 = new Key(21, "o1");
Object o2 = new Key(45, "o2");
AVLTree<Object, Object> t1 = AVLTree.create().add(o1).add(o2);
AVLTree<Object, Object> t2 = AVLTree.create().add(o2).add(o1);
assertThat(t1.key()).as("shape is different").isNotEqualTo(t2.key());
assertThat(t1.hashCode()).isEqualTo(t2.hashCode());
assertThat(t1).isEqualTo(t2);
assertThat(t2).isEqualTo(t1);
Object o3 = new Key(0, "o3");
AVLTree<Object, Object> t3 = t1.add(o3);
assertThat(t1.hashCode()).isEqualTo(t3.hashCode());
assertThat(t1).isNotEqualTo(t3);
assertThat(t3).isNotEqualTo(t1);
}
@Test
public void no_change() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "1");
assertThat(t1.put("1", "1")).isSameAs(t1);
assertThat(t1.remove("3")).isSameAs(t1);
AVLTree<String, String> t2 = t0.put("2", "2");
assertThat(t2.put("2", "2")).isSameAs(t2);
assertThat(t2.remove("3")).isSameAs(t2);
}
@Test
public void test_replace_root() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "a");
AVLTree<String, String> t2 = t1.put("1", "b");
assertThat(t1).isNotSameAs(t2);
assertThat(t1.get("1")).isEqualTo("a");
assertThat(t2.get("1")).isEqualTo("b");
}
@Test
public void balancing_should_preserve_buckets() {
Object k1 = new Key(1, "k1");
Object k2 = new Key(2, "k2");
Object k3 = new Key(3, "k3");
Object k4 = new Key(4, "k4");
AVLTree<Object, Object> t = AVLTree.create().put(k1, "v1").put(k2, "v2").put(k3, "v3");
Object k1_1 = new Key(1, "k1_1");
t = t.put(k1_1, "v1_1");
t = t.put(k4, "v4");
assertThat(t.height()).as("height after balancing").isEqualTo(3);
assertThat(t.get(k1_1)).isEqualTo("v1_1");
}
/**
* Subtraction must not be used for comparison of keys due to possibility of integer overflow,
* this for example will be the case for sequence below, which was generated using random number
* generator.
*/
@Test
public void do_not_use_subtraction_for_comparison_of_keys() {
Key[] keys = {
new Key(2043979982, ""),
new Key(-36348207, ""),
new Key(-1864559204, ""),
new Key(-2018458363, ""),
new Key(-152409201, ""),
new Key(-1786252453, ""),
new Key(-1853960690, "")
};
AVLTree<Object, Object> t = AVLTree.create();
for (Key key : keys) {
t = t.add(key);
}
for (Key key : keys) {
assertThat(t.get(key)).as("found").isNotNull();
assertThat(t.remove(key)).as("removed").isNotSameAs(t);
}
}
@Test
public void test_one_element() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "a");
AVLTree<String, String> t2 = t0.put("2", "b");
assertThat(t0).isNotSameAs(t1).isNotSameAs(t2);
assertThat(t1).isNotSameAs(t2);
assertThat(t0.get("1")).isNull();
assertThat(t0.get("2")).isNull();
assertThat(t0.get("3")).isNull();
assertThat(t1.get("1")).isEqualTo("a");
assertThat(t1.get("2")).isNull();
assertThat(t2.get("3")).isNull();
assertThat(t2.get("1")).isNull();
assertThat(t2.get("2")).isEqualTo("b");
assertThat(t2.get("3")).isNull();
}